Baker Hughes Masoneilan SVIII AP, Installation And Maintenance Manual

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Masoneilan SVI II AP Installation and Maintenance Manual =
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© 2017 Baker Hughes, a GE company, LLC. All rights reserved.
Figure 14 Model 33 Actuator
Rotary - 90°
For actuators with 60 to 120° rotation, follow the instructions in “Mounting the SVI II AP on
Rotary Valves” on page 39 except mount the magnet at plus or minus 45° while the actuator
de-energized as shown in Figure 14 on page 43.
Magnet Orientation on Rotary Valve Shafts
The same mounting hardware is used for Models 35, 30 actuators. For each actuator type the
magnetic coupling must be properly oriented to the active sensing angle of the positioners
Hall Effect sensor. The active range of the Hall-Effect sensor is plus
⁄ minus 70° from the null
magnet axis. If the total valve travel is less than 60°, allowing a margin for tolerances, the best
accuracy is achieved by mounting the magnet with the axis vertical in the valve-closed
position. The location of the magnets in the ring of the magnet holder. The axis of the magnets
is the line through the centers of both magnets. Mount the magnet holder with the magnet
axis vertical on the 35, 30 when the valve is closed. If travel of the valve exceeds 60°, the
magnet must be assembled to the rotary valve shaft so that the magnet axis is vertical when
the valve is at mid-scale.
Dismantling the SVI II AP from Rotary Valves
WARNING
Before carrying out any work on the device, power off the
instrument or make sure that the device’s location conditions for
potentially explosive atmosphere permit the safe opening of the
cover.
To remove the SVI II AP digital valve positioner from a rotary valve perform Steps 1 - 8 on
page 36 in reverse.